What's next for the lighting industry?

Issue 87 October / November 2015

Technology expert Dr Geoff Archenhold was recently a speaker at the LED Professional Symposium and Expo in Bregenz, Austria. Luckily for us, he hung around to find out what the future holds for the lighting industry in the next five years.

The last five years have shown the lighting industry changed by the potential of LEDs. With that being said, it will be the next five that see fundamental shifts. mondo*arc asked me to visit the LED Professional Symposium and Expo (LpS) in Bregenz, Austria to find out which new technologies will impact the industry in the near future.

The event began with the concept of design meets technology, with Rogier van der Heide discussing the second wave of lighting innovation – lighting beyond illumination. Over three days, parallel sessions from academia and industry, covered three topics areas: light quality; connectivity, security, reliability and lifetime; and standardisation and light measurement.

In terms of light quality, the three main topics of discussion were:

1.Human Centric Lighting (HCL): The non-visual effect of light on humans has gathered pace since the discovery of the third-receptor, known as the intrinsic photosensitive retinal ganglion cells (ipRGC) in the eye, providing evidence that light is capable of suppressing the hormone melatonin (attributed to good sleep patterns). A presentation by Zumtobel detailed the outcome of the ATKearney report for the potential of HCL within Europe, quantifying the benefits. At full market penetration, the macro simulations state that HCL effects can benefit up to a value of €12.8Bn in 2020 through improved productivity and healthier staff. The key challenge is to now understand the full impact of the ipRGC cells. The CIE has published a technical report (CIE TC3-46), identifying the challenges of understanding how the third cell affects the central nervous system. Several laboratory studies have shown HCL to impact health and well-being but reasons why are still not fully understood. However, I think the lighting industry will drive technical change with the ability to offer quality HCL for many applications.

2.Dynamic White and tuning CCT: The main discussion within this topic area was how HCL requires lighting to change both the CCT throughout the day as well as the relative intensities of the fixtures concurrently, posing a challenge for control solutions. An area leading the way is chronobiological adapted lighting, used by airlines to improve sleep on planes and promote greater alertness on arrival. A study by the Fraunhofer institute, Germany showed that bright blue light does two things. Firstly, it stimulates the stress hormone cortisol, creating alertness and secondly it suppresses melatonin. With HCL, as fixtures are dimmed and dynamically tuned in CCT, the human eye will detect colour changes and visible colour shifts when the CCT moves above or below the blackbody curve. Therefore, when colour tuning the CCT, the fixture should remain above or below but not exactly on the blackbody curve due to measurement errors. Light Cube and the University of Padova highlighted that, in order to implement HCL correctly, a complete lighting solution is needed, including: a control unit, simple human interface, control protocol and networking means, LED driver, multi-wavelength light sources and luminance, presence and other detectors. A straightforward HCL system would contain two white light sources, covering the extreme CCT requirements (warm white at 2,700K and cool white at 5,700K) as they are a broadband source of light, easier to design and control.

The main issue is that there are some clever (expensive) solutions appearing on the market with little evidence to prove whether such complicated solutions outweigh more straightforward approaches. Having HCL in my office, I can say that it improves the workplace compared to standard non-HCL based fixtures but I don’t know if I will see a substantial health benefit from a two-channel to three+ channels of HCL.

3.LED flicker: After years of discussing the health implications that the LED lighting industry has been inflicting by deploying systems that exhibit low frequency output current ripple, LpS discussed issues and possible solutions. Interestingly, flicker-free drivers were significantly discussed yet everyone also stated they used PWM to dim lights even if it was below 30%. Unfortunately, my definition of flicker-free lighting is: light amplitude output of a fixture shouldn’t deviate more than 25% at any forward current. I hear a great deal about the 100Hz flicker but in reality we should take note of studies that state operating LED flicker frequencies in the 1000 to 3000 Hz is the minimum. Also, many years ago a DIN standard stated: fluorescent lamps using electronic ballasts should be at least 30,000 Hz frequency, so I don’t see why the LED industry can’t deliver in advance of this at no extra cost. A start-up company, SwitchTech, from Sweden discussed the use of software to control LEDs in real-time and is definitely the way to go, providing the cost premium isn’t significantly high. Overall, flicker is on the agenda and that’s great for the industry moving forward.

An unaddressed area was how the lighting controls sector is falling behind the innovation cycle. I see advances in LED driving, colour control within fixtures, colour science understanding, thermal management and LED packaging but control systems still seem to be clunky, difficult to install, maintain and change, and struggle with new concepts such as HCL. Perhaps that will be the industry focus in 2016.

Geoff Archenhold is an active investor in LED driver and fixture manufacturers and a lighting energy consultant. The views expressed in this article are those of the author and do not necessarily represent the views of mondo*arc.